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<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
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<body>
  <script>
   //可以使用typeof操作符来确定任意变量的数据类型
   var a = 1
   console.log(typeof a);
   
  </script>
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